Long confused with Ipomoeagracilis R. Brown, a distinct species that is endemic to Australia; the nomenclature, distribution, and ethnobotanical significance of I.littoralis have been discussed by Austin (Econ. Bot. 45: 251-256. 1991).

According to Xing et al. (Guihaia 14: 151-156. 1994) and Huang et al. (Taiwania 39: 1-26. 1994), Ipomoea gracilis R. Brown occurs on the South China Sea Islands (Nanhai Zhudao);
however, material was not available for study. It is likely that the plants collected belong to I. littoralis, and not I. gracilis.